Figure 26.4 A carrier (porter) transports a
solute into the cell by a conformational change that brings the
solute-binding site from the exterior to the interior, while an ion
channel is controlled by the opening of a gate (which might in principle
be located on either side of the membrane).Multiple
figure

Figure 26.5 A channel may be created by
amphipathic helices, which present their hydrophobic faces to the lipid
bilayer, while juxtaposing their charged faces away from the bilayer. In
this example, the channel is lined with positive charges, which would
encourage the passage of anions.